E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include a top-shaped fruitbody with the cap mauve, pale blue, whitish, or tan when young, becoming dark brown from the center outward, with similar colors in the cap flesh but rusty-colored in the stem flesh, whitish to bluish young teeth that become brown with pale tips, and a tough rooting stem covered with debris. It may have a strong farinaceous odor and taste. Hydnellum caeruleum is common in the Pacific Northwest (Arora).

Distribution includes WA (Hall), BC (collections at Pacific Forestry Centre including one determined by K.A. Harrison), and OR (collections at Oregon State University). The University of Washington also has a collection from AK. It is relatively common in the northern conifer areas of North America (including MI) and Europe, (Harrison) and is also found in temperate Asia (Trudell).

Cap:
3-12(17)cm, top-shaped becoming flat or slightly depressed, often with needles or leaves incorporated; "mauve to pale blue, whitish or tan when young, becoming light to dull dark brown or even blackish from the center outward", the soft felty growing margin white or pale blue to bluish gray; "felty or velvety at first, often bumpy and/or pitted" when old and with matted hairs, (Arora), 3-11cm, convex, flat, sometimes depressed; "light blue when young, becoming almost white", gradually darkening when old to dark brown, "staining ferruginous when bruised"; smooth, or irregular to colliculose [bumpy], cottony tomentose, finally matted and pitted, (Harrison(3)), fruitbody up to 11cm tall, cap up to 17cm broad, flat or when old depressed, margin uneven, wavy, thick when young, becoming thin when old; "Vandyke brown" to "burnt umber" on disc, becoming "vinaceous-russet" to "pale ochraceous-buff" or "tilleul-buff" ("vinaceous-fawn", "pinkish cinnamon" or "pale pinkish buff") toward the margin, margin becoming pale "cinnamon-buff" to "light vinaceous-cinnamon", "lavender" or "pallid violet" ("light gull gray", "grayish lavender", "plumbago blue"), (Ridgway colors), becoming blackish brown when bruised towards and at margin; cap surface "nodulose, pitted, tomentose or strigose-hairy", (Hall), stains rusty brown when bruised (McKnight)

Flesh:
"duplex: upper or outer layer spongy, inner core tough and fibrous, zoned variously with bluish, blue-gray, mauve, and brown in the cap", bright rusty-colored to orange-red in stem, (Arora), duplex, upper layer spongy, "lower layer tough, fibrous compact, buff", zoned with bands of mauve and brown, shading to a reddish brown to ferruginous in lower part of stem; in stem "outer layer thin, inner layer orange or reddish, lighter parts frequently with bands of blue, tough and fibrous", thick felty layer around base often disappearing from being eaten by slugs, (Harrison(3)), up to 3cm thick at stem, duplex, the upper spongy layer blue to violet-black, the lower fibrous woody layer zoned, "carnelian red" to "Hay''s russet"; in stem duplex, with corky outer layer surrounding inner fibrous-woody core that is colored "carnelian red" to "Hay''s russet", (Ridgway colors), (Hall), stem interior orange to rusty brown, with zones of blue (McKnight), cap flesh bluish to grayish to nearly back, stem flesh red-brown to orange-brown, (Trudell)

Teeth:
0.1-0.5cm, often decurrent; "whitish when young or tinged blue", becoming brown to dark brown with pallid tips when old, (Arora), 0.3-0.5cm long, decurrent, close, fine; "on the margin whitish with a shade of blue, finally dark brown with lighter tips", (Harrison(3)), up to 1cm long, 5-6 per square mm, decurrent, fleshy, round in cross-section, subulate [awl-shaped], "pale pinkish cinnamon" to "pale pinkish buff" or "vinaceous-cinnamon" ("seashell pink", "pale salmon color", "salmon color" or "ochraceous-salmon"), becoming "Verona brown" to "snuff brown" or "hazel" when bruised, (Ridgway colors), dwindling to tubercles near margin, the marginal 0.2-0.3cm lighter colored than the rest of the spore-bearing surface, (Hall)

Stem:
2-9(12)cm x 1-3cm, "central or off-center, very tough, often rooting deeply in humus", equal or wider at either end; "buff to brown or orange-brown, but usually covered with debris", (Arora), 2-4cm x 1-2cm, "base bulbous from felty mycelium, buff colored", (Harrison(3)), 7cm x 3cm, central to off-center, base not swollen, (Hall), mycelium straw-colored (Lincoff)

Chemical Reactions:
blue parts turn blue-green and reddish parts turn dark dull olive with KOH (McKnight)

Odor:
strong farinaceous (Arora, Hall), not distinctive (McKnight, Harrison(3)), slightly farinaceous (Breitenbach), none or slightly of cooked meat (Bessette), heavy and unpleasant, anise-like, (Miller)

Taste:
strong farinaceous (Arora, Hall), not distinctive (McKnight, Harrison(3)), mild (Breitenbach), mild or slightly acid (Bessette), mild but slightly unpleasant (Miller)

Microscopic:
spores 4.5-7 x 3.5-5 microns, nearly round to elliptic and irregularly lobed or warted, (Arora), spores 4.5-6(7) x 4.5-5 microns, nearly round, coarsely tuberculate; basidia 4-spored, 6-7 microns wide; blackish granules on the hyphae of the teeth give apparent amyloid effect, some sections of context have blackish granules in water and in Melzer''s reagent, (Harrison(3)), spores 4.7-6.0 x 3.5-4.7 microns, round to elliptic, minutely tuberculate, inamyloid; basidia 4-spored, 35-45 x 5.3-7.3 microns, clavate; hyphae "to 5 microns in diam, colorless, thin-walled, with infrequent clamps in the spongy pileus context, septate, branched, interwoven in the upper context, parallel in the fibrous lower context", (Hall), spores 4.5-6 x 3.5-5.5 microns (Bessette)

Spore Deposit:
fawn brown (Hall), brown (Arora), vinaceous brown (Harrison(3)), light brown (Bessette)